diff --git a/src/JsonSchema/TypeFactory.php b/src/JsonSchema/TypeFactory.php
index b6825ceaf70..f3d3f48a63e 100644
--- a/src/JsonSchema/TypeFactory.php
+++ b/src/JsonSchema/TypeFactory.php
@@ -50,14 +50,27 @@ public function setSchemaFactory(SchemaFactoryInterface $schemaFactory): void
     public function getType(Type $type, string $format = 'json', ?bool $readableLink = null, ?array $serializerContext = null, Schema $schema = null): array
     {
         if ($type->isCollection()) {
-            $subType = new Type($type->getBuiltinType(), $type->isNullable(), $type->getClassName(), false);
+            $keyType = $type->getCollectionKeyType();
+            $subType = $type->getCollectionValueType() ?? new Type($type->getBuiltinType(), false, $type->getClassName(), false);
 
-            return [
+            if (null !== $keyType && Type::BUILTIN_TYPE_STRING === $keyType->getBuiltinType()) {
+                return $this->addNullabilityToTypeDefinition([
+                    'type' => 'object',
+                    'additionalProperties' => $this->getType($subType, $format, $readableLink, $serializerContext, $schema),
+                ], $type, $schema);
+            }
+
+            return $this->addNullabilityToTypeDefinition([
                 'type' => 'array',
                 'items' => $this->getType($subType, $format, $readableLink, $serializerContext, $schema),
-            ];
+            ], $type, $schema);
         }
 
+        return $this->addNullabilityToTypeDefinition($this->makeBasicType($type, $format, $readableLink, $serializerContext, $schema), $type, $schema);
+    }
+
+    private function makeBasicType(Type $type, string $format = 'json', ?bool $readableLink = null, ?array $serializerContext = null, Schema $schema = null): array
+    {
         switch ($type->getBuiltinType()) {
             case Type::BUILTIN_TYPE_INT:
                 return ['type' => 'integer'];
@@ -75,7 +88,7 @@ public function getType(Type $type, string $format = 'json', ?bool $readableLink
     /**
      * Gets the JSON Schema document which specifies the data type corresponding to the given PHP class, and recursively adds needed new schema to the current schema if provided.
      */
-    private function getClassType(?string $className, string $format = 'json', ?bool $readableLink = null, ?array $serializerContext = null, ?Schema $schema = null): array
+    private function getClassType(?string $className, string $format, ?bool $readableLink, ?array $serializerContext, ?Schema $schema): array
     {
         if (null === $className) {
             return ['type' => 'string'];
@@ -125,4 +138,29 @@ private function getClassType(?string $className, string $format = 'json', ?bool
 
         return ['$ref' => $subSchema['$ref']];
     }
+
+    /**
+     * @param array<string, mixed> $jsonSchema
+     *
+     * @return array<string, mixed>
+     */
+    private function addNullabilityToTypeDefinition(array $jsonSchema, Type $type, ?Schema $schema): array
+    {
+        if ($schema && Schema::VERSION_SWAGGER === $schema->getVersion()) {
+            return $jsonSchema;
+        }
+
+        if (!$type->isNullable()) {
+            return $jsonSchema;
+        }
+
+        if (\array_key_exists('$ref', $jsonSchema)) {
+            return [
+                'nullable' => true,
+                'anyOf' => [$jsonSchema],
+            ];
+        }
+
+        return array_merge($jsonSchema, ['nullable' => true]);
+    }
 }
diff --git a/tests/JsonSchema/TypeFactoryTest.php b/tests/JsonSchema/TypeFactoryTest.php
index 000b05aea36..7f6259501ed 100644
--- a/tests/JsonSchema/TypeFactoryTest.php
+++ b/tests/JsonSchema/TypeFactoryTest.php
@@ -29,19 +29,225 @@ class TypeFactoryTest extends TestCase
     public function testGetType(array $schema, Type $type): void
     {
         $typeFactory = new TypeFactory();
-        $this->assertSame($schema, $typeFactory->getType($type));
+        $this->assertEquals($schema, $typeFactory->getType($type, 'json', null, null, new Schema()));
     }
 
     public function typeProvider(): iterable
     {
         yield [['type' => 'integer'], new Type(Type::BUILTIN_TYPE_INT)];
+        yield [['nullable' => true, 'type' => 'integer'], new Type(Type::BUILTIN_TYPE_INT, true)];
         yield [['type' => 'number'], new Type(Type::BUILTIN_TYPE_FLOAT)];
+        yield [['nullable' => true, 'type' => 'number'], new Type(Type::BUILTIN_TYPE_FLOAT, true)];
         yield [['type' => 'boolean'], new Type(Type::BUILTIN_TYPE_BOOL)];
+        yield [['nullable' => true, 'type' => 'boolean'], new Type(Type::BUILTIN_TYPE_BOOL, true)];
+        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_STRING)];
+        yield [['nullable' => true, 'type' => 'string'], new Type(Type::BUILTIN_TYPE_STRING, true)];
         yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_OBJECT)];
+        yield [['nullable' => true, 'type' => 'string'], new Type(Type::BUILTIN_TYPE_OBJECT, true)];
         yield [['type' => 'string', 'format' => 'date-time'], new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateTimeImmutable::class)];
+        yield [['nullable' => true, 'type' => 'string', 'format' => 'date-time'], new Type(Type::BUILTIN_TYPE_OBJECT, true, \DateTimeImmutable::class)];
         yield [['type' => 'string', 'format' => 'duration'], new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateInterval::class)];
-        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_OBJECT, false, Dummy::class)];
+        yield [['type' => 'string', 'format' => 'iri-reference'], new Type(Type::BUILTIN_TYPE_OBJECT, false, Dummy::class)];
+        yield [['nullable' => true, 'type' => 'string', 'format' => 'iri-reference'], new Type(Type::BUILTIN_TYPE_OBJECT, true, Dummy::class)];
         yield [['type' => 'array', 'items' => ['type' => 'string']], new Type(Type::BUILTIN_TYPE_STRING, false, null, true)];
+        yield 'array can be itself nullable' => [
+            ['nullable' => true, 'type' => 'array', 'items' => ['type' => 'string']],
+            new Type(Type::BUILTIN_TYPE_STRING, true, null, true),
+        ];
+
+        yield 'array can contain nullable values' => [
+            [
+                'type' => 'array',
+                'items' => [
+                    'nullable' => true,
+                    'type' => 'string',
+                ],
+            ],
+            new Type(Type::BUILTIN_TYPE_STRING, false, null, true, null, new Type(Type::BUILTIN_TYPE_STRING, true, null, false)),
+        ];
+
+        yield 'map with string keys becomes an object' => [
+            ['type' => 'object', 'additionalProperties' => ['type' => 'string']],
+            new Type(
+                Type::BUILTIN_TYPE_STRING,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false)
+            ),
+        ];
+
+        yield 'nullable map with string keys becomes a nullable object' => [
+            [
+                'nullable' => true,
+                'type' => 'object',
+                'additionalProperties' => ['type' => 'string'],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_STRING,
+                true,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false)
+            ),
+        ];
+
+        yield 'map value type will be considered' => [
+            ['type' => 'object', 'additionalProperties' => ['type' => 'integer']],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, false, null, false)
+            ),
+        ];
+
+        yield 'map value type nullability will be considered' => [
+            [
+                'type' => 'object',
+                'additionalProperties' => [
+                    'nullable' => true,
+                    'type' => 'integer',
+                ],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, true, null, false)
+            ),
+        ];
+
+        yield 'nullable map can contain nullable values' => [
+            [
+                'nullable' => true,
+                'type' => 'object',
+                'additionalProperties' => [
+                    'nullable' => true,
+                    'type' => 'integer',
+                ],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                true,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, true, null, false)
+            ),
+        ];
+    }
+
+    /** @dataProvider openAPIV2typeProvider */
+    public function testGetTypeWithOpenAPIV2Syntax(array $schema, Type $type): void
+    {
+        $typeFactory = new TypeFactory();
+        $this->assertSame($schema, $typeFactory->getType($type, 'json', null, null, new Schema(Schema::VERSION_SWAGGER)));
+    }
+
+    public function openAPIV2typeProvider(): iterable
+    {
+        yield [['type' => 'integer'], new Type(Type::BUILTIN_TYPE_INT)];
+        yield [['type' => 'integer'], new Type(Type::BUILTIN_TYPE_INT, true)];
+        yield [['type' => 'number'], new Type(Type::BUILTIN_TYPE_FLOAT)];
+        yield [['type' => 'number'], new Type(Type::BUILTIN_TYPE_FLOAT, true)];
+        yield [['type' => 'boolean'], new Type(Type::BUILTIN_TYPE_BOOL)];
+        yield [['type' => 'boolean'], new Type(Type::BUILTIN_TYPE_BOOL, true)];
+        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_STRING)];
+        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_STRING, true)];
+        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_OBJECT)];
+        yield [['type' => 'string'], new Type(Type::BUILTIN_TYPE_OBJECT, true)];
+        yield [['type' => 'string', 'format' => 'date-time'], new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateTimeImmutable::class)];
+        yield [['type' => 'string', 'format' => 'date-time'], new Type(Type::BUILTIN_TYPE_OBJECT, true, \DateTimeImmutable::class)];
+        yield [['type' => 'string', 'format' => 'duration'], new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateInterval::class)];
+        yield [['type' => 'string', 'format' => 'iri-reference'], new Type(Type::BUILTIN_TYPE_OBJECT, false, Dummy::class)];
+        yield [['type' => 'string', 'format' => 'iri-reference'], new Type(Type::BUILTIN_TYPE_OBJECT, true, Dummy::class)];
+        yield [['type' => 'array', 'items' => ['type' => 'string']], new Type(Type::BUILTIN_TYPE_STRING, false, null, true)];
+        yield 'array can be itself nullable, but ignored in OpenAPI V2' => [
+            ['type' => 'array', 'items' => ['type' => 'string']],
+            new Type(Type::BUILTIN_TYPE_STRING, true, null, true),
+        ];
+
+        yield 'array can contain nullable values, but ignored in OpenAPI V2' => [
+            [
+                'type' => 'array',
+                'items' => ['type' => 'string'],
+            ],
+            new Type(Type::BUILTIN_TYPE_STRING, false, null, true, null, new Type(Type::BUILTIN_TYPE_STRING, true, null, false)),
+        ];
+
+        yield 'map with string keys becomes an object' => [
+            ['type' => 'object', 'additionalProperties' => ['type' => 'string']],
+            new Type(
+                Type::BUILTIN_TYPE_STRING,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false)
+            ),
+        ];
+
+        yield 'nullable map with string keys becomes a nullable object, but ignored in OpenAPI V2' => [
+            [
+                'type' => 'object',
+                'additionalProperties' => ['type' => 'string'],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_STRING,
+                true,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false)
+            ),
+        ];
+
+        yield 'map value type will be considered' => [
+            ['type' => 'object', 'additionalProperties' => ['type' => 'integer']],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, false, null, false)
+            ),
+        ];
+
+        yield 'map value type nullability will be considered, but ignored in OpenAPI V2' => [
+            [
+                'type' => 'object',
+                'additionalProperties' => ['type' => 'integer'],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                false,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, true, null, false)
+            ),
+        ];
+
+        yield 'nullable map can contain nullable values, but ignored in OpenAPI V2' => [
+            [
+                'type' => 'object',
+                'additionalProperties' => ['type' => 'integer'],
+            ],
+            new Type(
+                Type::BUILTIN_TYPE_ARRAY,
+                true,
+                null,
+                true,
+                new Type(Type::BUILTIN_TYPE_STRING, false, null, false),
+                new Type(Type::BUILTIN_TYPE_INT, true, null, false)
+            ),
+        ];
     }
 
     public function testGetClassType(): void
@@ -59,4 +265,30 @@ public function testGetClassType(): void
 
         $this->assertSame(['$ref' => 'ref'], $typeFactory->getType(new Type(Type::BUILTIN_TYPE_OBJECT, false, Dummy::class), 'jsonld', true, ['foo' => 'bar'], new Schema()));
     }
+
+    public function testGetClassTypeWithNullability(): void
+    {
+        $schemaFactory = $this->createMock(SchemaFactoryInterface::class);
+
+        $schemaFactory
+            ->method('buildSchema')
+            ->willReturnCallback(static function (): Schema {
+                $schema = new Schema();
+
+                $schema['$ref'] = 'the-ref-name';
+                $schema['description'] = 'more stuff here';
+
+                return $schema;
+            });
+
+        $typeFactory = new TypeFactory();
+        $typeFactory->setSchemaFactory($schemaFactory);
+
+        self::assertSame([
+            'nullable' => true,
+            'anyOf' => [
+                ['$ref' => 'the-ref-name'],
+            ],
+        ], $typeFactory->getType(new Type(Type::BUILTIN_TYPE_OBJECT, true, Dummy::class), 'jsonld', true, ['foo' => 'bar'], new Schema()));
+    }
 }
diff --git a/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php b/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
index 684da2d83a4..7956cdea209 100644
--- a/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
+++ b/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
@@ -344,9 +344,10 @@ private function doTestNormalize(OperationMethodResolverInterface $operationMeth
                         ]),
                         'dummyDate' => new \ArrayObject([
                             'type' => 'string',
-                            'description' => 'This is a \DateTimeInterface object.',
                             'format' => 'date-time',
-                        ]),                     ],
+                            'description' => 'This is a \DateTimeInterface object.',
+                        ]),
+                    ],
                 ]),
             ]),
         ];
@@ -380,13 +381,19 @@ private function doTestNormalizeWithNameConverter(bool $legacy = false): void
         $propertyMetadataFactoryProphecy->create(Dummy::class, 'name')->shouldBeCalled()->willReturn(new PropertyMetadata(new Type(Type::BUILTIN_TYPE_STRING), 'This is a name.', true, true, null, null, false));
         $propertyMetadataFactoryProphecy->create(Dummy::class, 'nameConverted')->shouldBeCalled()->willReturn(new PropertyMetadata(new Type(Type::BUILTIN_TYPE_STRING), 'This is a converted name.', true, true, null, null, false));
 
-        $nameConverterProphecy = $this->prophesize(
-            interface_exists(AdvancedNameConverterInterface::class)
-                ? AdvancedNameConverterInterface::class
-                : NameConverterInterface::class
-        );
-        $nameConverterProphecy->normalize('name', Dummy::class, DocumentationNormalizer::FORMAT, [])->willReturn('name')->shouldBeCalled();
-        $nameConverterProphecy->normalize('nameConverted', Dummy::class, DocumentationNormalizer::FORMAT, [])->willReturn('name_converted')->shouldBeCalled();
+        if (interface_exists(AdvancedNameConverterInterface::class)) {
+            $nameConverter = $this->createMock(AdvancedNameConverterInterface::class);
+        } else {
+            $nameConverter = $this->createMock(NameConverterInterface::class);
+        }
+
+        $nameConverter->method('normalize')
+            ->with(self::logicalOr('name', 'nameConverted'))
+            ->willReturnCallback(static function (string $nameToNormalize): string {
+                return 'nameConverted' === $nameToNormalize
+                    ? 'name_converted'
+                    : $nameToNormalize;
+            });
 
         $operationPathResolver = new CustomOperationPathResolver(new OperationPathResolver(new UnderscorePathSegmentNameGenerator()));
 
@@ -402,10 +409,6 @@ interface_exists(AdvancedNameConverterInterface::class)
          * @var PropertyMetadataFactoryInterface
          */
         $propertyMetadataFactory = $propertyMetadataFactoryProphecy->reveal();
-        /**
-         * @var NameConverterInterface
-         */
-        $nameConverter = $nameConverterProphecy->reveal();
 
         /**
          * @var TypeFactoryInterface|null
diff --git a/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php b/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
index 125add993c0..96406c4174d 100644
--- a/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
+++ b/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
@@ -385,9 +385,10 @@ private function doTestNormalize(OperationMethodResolverInterface $operationMeth
                                 'description' => 'This is an initializable but not writable property.',
                             ]),
                             'dummyDate' => new \ArrayObject([
+                                'nullable' => true,
                                 'type' => 'string',
-                                'description' => 'This is a \DateTimeInterface object.',
                                 'format' => 'date-time',
+                                'description' => 'This is a \DateTimeInterface object.',
                             ]),
                         ],
                     ]),
@@ -2000,7 +2001,10 @@ public function testNormalizeWithNestedNormalizationGroups(): void
                             ]),
                             'relatedDummy' => new \ArrayObject([
                                 'description' => 'This is a related dummy \o/.',
-                                '$ref' => '#/components/schemas/'.$relatedDummyRef,
+                                'nullable' => true,
+                                'anyOf' => [
+                                    ['$ref' => '#/components/schemas/'.$relatedDummyRef],
+                                ],
                             ]),
                         ],
                     ]),